Propranolol belongs to a group of medicines called beta blockers. It's used to treat heart problems, help with anxiety and prevent migraines.

If you have a heart problem, you can take propranolol to:

• treat high blood pressure
• treat conditions that cause an irregular heartbeat (arrhythmia), like atrial fibrillation
• help prevent future heart disease, heart attacks and strokes
• help prevent chest pain caused by angina

Propranolol can help reduce your symptoms if you have too much thyroid hormone in your body (thyrotoxicosis). You'll usually take it together with medicines to treat an overactive thyroid.

This medicine is only available on prescription. It comes as tablets, slow release capsules, or as a liquid that you swallow.

• Propranolol slows down your heart rate and makes it easier for your heart to pump blood around your body.
• It's usually prescribed for high blood pressure and other heart problems, but it can also help with the physical signs of anxiety, like sweating and shaking.
• Your very first dose of propranolol may make you feel dizzy, so take it at bedtime. After that, if you do not feel dizzy, you can take it in the morning.
• The main side effects of propranolol are feeling dizzy or tired, cold hands or feet, difficulties sleeping and nightmares. These side effects are usually mild and short-lived.

Most adults and children aged 12 and over can take propranolol. But it is not officially approved for treating high blood pressure in children under 12 years old.

Propranolol is not suitable for everyone. To make sure it's safe for you, tell your doctor before starting to take propranolol if you:

• have ever had an allergic reaction to propranolol or any other medicine
• have low blood pressure or a slow heart rate
• have heart failure which is getting worse
• have diabetes
• have liver or kidney problems
• have severe blood circulation problems in your limbs (such as Raynaud's phenomenon), which may make your fingers and toes tingle or turn paler than usual or blue
• have metabolic acidosis, when there is too much acid in your blood
• have lung disease or asthma
• are pregnant, trying to get pregnant or breastfeeding

Propranolol comes as 2 different types of medicine:

• standard release – this releases propranolol into your body quickly, so you may need to take it several times a day depending on your dose
• slow release – this releases the medicine slowly so you do not have to take it as often, once a day is usually enough

If you are taking it once a day, your doctor may advise you to take your first dose before bedtime, because it can make you feel dizzy. After the first dose, if you do not feel dizzy, take propranolol in the morning.

Like all medicines, propranolol can cause side effects in some people, but many people have no side effects or only minor ones.

Side effects often improve as your body gets used to the medicine.

Common side effects

These common side effects happen in more than 1 in 100 people. They're usually mild and short-lived.

Talk to your doctor or pharmacist if the side effects bother you or last more than a few days:

• headaches
• feeling tired, dizzy or weak
• cold fingers or toes
• feeling or being sick (nausea or vomiting), or diarrhoea
• stomach pain

Serious side effects

It happens rarely, but some people have serious side effects when taking propranolol.

Tell a doctor or contact 111 straight away if:

• the whites of your eyes turn yellow, your skin turns yellow although this may be less obvious on brown on black skin, or you have pale poo or dark pee – these can be signs of liver problems
• you get nosebleeds that last for more than 10 minutes, unexplained bruising, or you bruise more easily than usual – these can be signs of low numbers of platelets in your blood (thrombocytopenia)

Go to 111.nhs.uk or call 111.

What to do about:

• headaches – make sure you rest and drink plenty of fluids. Try not to drink too much alcohol. Ask your pharmacist to recommend a painkiller. Talk to your doctor if the headaches last longer than a week or are severe.
• feeling tired, dizzy or weak – as your body gets used to propranolol, these side effects should wear off. If propranolol makes you feel dizzy, sit or lie down until you feel better. It's best not to drink alcohol as it will make you feel worse. Do not drive or ride a bike until you feel better.
• cold fingers or toes – put your hands or feet under warm running water, massage them and wiggle your fingers and toes. Do not smoke or have drinks with caffeine in, as this can make your blood vessels narrower and further restrict blood flow to your hands and feet. Try wearing mittens (they're warmer than gloves) and warm socks. Do not wear tight watches or bracelets.
• feeling or being sick or diarrhoea – stick to simple meals and do not eat rich or spicy food. It might help to take your propranolol after a meal or snack. Drink lots of fluids, such as water or squash, to avoid dehydration. Take small, frequent sips if you're being sick. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee. Do not take any other medicines to treat diarrhoea and vomiting without speaking to a pharmacist or doctor. If you take contraceptive pills and you're being sick or have severe diarrhoea, your contraception may not protect you from pregnancy. Check the pill packet for advice.
• stomach pain – try to rest and relax. It can help to eat and drink slowly and have smaller and more frequent meals. Putting a heat pad or covered hot water bottle on your tummy may also help. If you are in a lot of pain, speak to your pharmacist or doctor.

Propranolol is not thought to be harmful during pregnancy, but it may affect your baby's growth in later pregnancy. Discuss taking propranolol with your doctor or midwife as you may need extra scans to check your baby's growth.

If you're trying to get pregnant or you're already pregnant, talk to your doctor about the benefits and possible harms of taking propranolol. There may be other medicines that are better to use during pregnancy.

Propranolol and breastfeeding

If your doctor or health visitor says that your baby is healthy, it's OK to take propranolol while breastfeeding.

Propranolol passes into breast milk in tiny amounts. It has not been known to cause any side effects in breastfed babies.

It's important to treat your high blood pressure to keep you well. Breastfeeding will also benefit both you and your baby.

If you notice that your baby is not feeding as well as usual, or seems unusually sleepy, or if you have any other concerns about your baby, then talk to your doctor or health visitor.

For more information about how propranolol can affect you and your baby during pregnancy, visit the Best Use of Medicines in Pregnancy (BUMPS) website.

There are some medicines that may affect the way propranolol works.

Tell your doctor if you're taking:

• other medicines for high blood pressure. The combination with propranolol can sometimes lower your blood pressure too much. This may make you feel dizzy or faint. If this keeps happening to you, your doctor may change your dose
• other medicines for an irregular heartbeat such as amiodarone or flecainide
• other medicines which can lower your blood pressure. These include some antidepressants, nitrates (for chest pain), baclofen (a muscle relaxant), medicines for an enlarged prostate gland like tamsulosin, or Parkinson's disease medicines such as levodopa
• asthma or chronic obstructive pulmonary disease (COPD) medicines
• diabetes medicines, particularly insulin – propranolol may make it more difficult to recognise the warning signs of low blood sugar. Speak to your doctor if you have low blood sugar levels without getting any of the usual warning signs. Check your blood sugar after exercise, and follow usual advice about checking it before driving, cycling or operating machinery
• medicines to treat nose or sinus congestion, or other cold remedies (including those you can buy in the pharmacy)
• medicines for allergies, such as ephedrine, noradrenaline or adrenaline
• non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, diclofenac or naproxen. These medicines may increase your blood pressure, so it's best to keep them to a minimum

Mixing propranolol with herbal remedies or supplements

There's very little information about taking herbal remedies and supplements with propranolol. They are not tested in the same way as pharmacy and prescription medicines.